private void SolveTOI(TimeStep step)
{
Island island = new Island(m_contactManager.m_contactListener);
if (m_stepComplete)
{
foreach (Body b in m_bodyList)
{
b.m_flags &= ~Body.BodyFlags.e_islandFlag;
b.m_sweep.alpha0 = 0.0f;
}
foreach (Contact c in m_contactManager.m_contactList)
{
// Invalidate TOI
c.m_flags &= ~(ContactFlags.e_toiFlag | ContactFlags.e_islandFlag);
c.m_toiCount = 0;
c.m_toi = 1.0f;
}
}
Fixture fA = null;
Fixture fB = null;
Body bA = null;
Body bB = null;
// Find TOI events and solve them.
for (;;)
{
// Find the first TOI.
Contact minContact = null;
float minAlpha = 1.0f;
foreach (Contact c in m_contactManager.m_contactList)
{
// Is this contact disabled?
if (c.IsEnabled() == false)
{
continue;
}
// Prevent excessive sub-stepping.
if (c.m_toiCount > Settings._maxSubSteps)
{
continue;
}
float alpha = 1.0f;
if (c.m_flags.HasFlag(ContactFlags.e_toiFlag))
{
// This contact has a valid cached TOI.
alpha = c.m_toi;
}
else
{
fA = c.FixtureA;
fB = c.FixtureB;
// Is there a sensor?
if (fA.IsSensor || fB.IsSensor)
{
continue;
}
bA = fA.GetBody();
bB = fB.GetBody();
BodyType typeA = bA.m_type;
BodyType typeB = bB.m_type;
Utilities.Assert(typeA == BodyType._dynamicBody || typeB == BodyType._dynamicBody);
bool activeA = bA.IsAwake() && typeA != BodyType._staticBody;
bool activeB = bB.IsAwake() && typeB != BodyType._staticBody;
// Is at least one body active (awake and dynamic or kinematic)?
if (activeA == false && activeB == false)
{
continue;
}
bool collideA = bA.IsBullet() || typeA != BodyType._dynamicBody;
bool collideB = bB.IsBullet() || typeB != BodyType._dynamicBody;
// Are these two non-bullet dynamic bodies?
if (collideA == false && collideB == false)
{
continue;
}
// Compute the TOI for this contact.
// Put the sweeps onto the same time interval.
float alpha0 = bA.m_sweep.alpha0;
if (bA.m_sweep.alpha0 < bB.m_sweep.alpha0)
{
alpha0 = bB.m_sweep.alpha0;
bA.m_sweep.Advance(alpha0);
}
else if (bB.m_sweep.alpha0 < bA.m_sweep.alpha0)
{
alpha0 = bA.m_sweep.alpha0;
bB.m_sweep.Advance(alpha0);
}
Utilities.Assert(alpha0 < 1.0f);
int indexA = c.GetChildIndexA();
int indexB = c.GetChildIndexB();
// Compute the time of impact in interval [0, minTOI]
TOIInput input = new TOIInput();
input.proxyA.Set(fA.GetShape(), indexA);
input.proxyB.Set(fB.GetShape(), indexB);
input.sweepA = bA.m_sweep;
input.sweepB = bB.m_sweep;
input.tMax = 1.0f;
TOIOutput output;
Utilities.TimeOfImpact(out output, input);
// Beta is the fraction of the remaining portion of the .
float beta = output.t;
if (output.state == TOIOutput.State.e_touching)
{
alpha = Math.Min(alpha0 + (1.0f - alpha0) * beta, 1.0f);
}
else
{
alpha = 1.0f;
}
c.m_toi = alpha;
c.m_flags |= ContactFlags.e_toiFlag;
}
if (alpha < minAlpha)
{
// This is the minimum TOI found so far.
minContact = c;
minAlpha = alpha;
}
}
if (minContact == null || 1.0f - 10.0f * Single.Epsilon < minAlpha)
{
// No more TOI events. Done!
m_stepComplete = true;
break;
}
// Advance the bodies to the TOI.
fA = minContact.FixtureA;
fB = minContact.FixtureB;
bA = fA.GetBody();
bB = fB.GetBody();
Sweep backup1 = bA.m_sweep;
Sweep backup2 = bB.m_sweep;
bA.Advance(minAlpha);
bB.Advance(minAlpha);
// The TOI contact likely has some new contact points.
minContact.Update(m_contactManager.m_contactListener);
minContact.m_flags &= ~ContactFlags.e_toiFlag;
++minContact.m_toiCount;
// Is the contact solid?
if (minContact.IsEnabled() == false || minContact.IsTouching() == false)
{
// Restore the sweeps.
minContact.SetEnabled(false);
bA.m_sweep = backup1;
bB.m_sweep = backup2;
bA.SynchronizeTransform();
bB.SynchronizeTransform();
continue;
}
bA.SetAwake(true);
bB.SetAwake(true);
// Build the island
island.Clear();
island.Add(bA);
island.Add(bB);
island.Add(minContact);
bA.m_flags |= Body.BodyFlags.e_islandFlag;
bB.m_flags |= Body.BodyFlags.e_islandFlag;
minContact.m_flags |= ContactFlags.e_islandFlag;
// Get contacts on bodyA and bodyB.
Body[] bodies = { bA, bB };
for (int i = 0; i < 2; ++i)
{
Body body = bodies[i];
if (body.m_type == BodyType._dynamicBody)
{
foreach (ContactEdge ce in body.m_contactList)
{
throw new NotImplementedException();
//if (island.m_bodies.Count() == island.m_bodyCapacity)
//{
// break;
//}
//if (island.m_bodies.Count() == island.m_contactCapacity)
//{
// break;
//}
//Contact* contact = ce.contact;
//// Has this contact already been added to the island?
//if (contact.m_flags & ContactFlags.e_islandFlag)
//{
// continue;
//}
//// Only add static, kinematic, or bullet bodies.
//Body* other = ce.other;
//if (other.m_type == _dynamicBody &&
// body.IsBullet() == false && other.IsBullet() == false)
//{
// continue;
//}
//// Skip sensors.
//bool sensorA = contact.m_fixtureA.m_isSensor;
//bool sensorB = contact.m_fixtureB.m_isSensor;
//if (sensorA || sensorB)
//{
// continue;
//}
//// Tentatively advance the body to the TOI.
//Sweep backup = other.m_sweep;
//if ((other.m_flags & Body.BodyFlags.e_islandFlag) == 0)
//{
// other.Advance(minAlpha);
//}
//// Update the contact points
//contact.Update(m_contactManager.m_contactListener);
//// Was the contact disabled by the user?
//if (contact.IsEnabled() == false)
//{
// other.m_sweep = backup;
// other.SynchronizeTransform();
// continue;
//}
//// Are there contact points?
//if (contact.IsTouching() == false)
//{
// other.m_sweep = backup;
// other.SynchronizeTransform();
// continue;
//}
//// Add the contact to the island
//contact.m_flags |= ContactFlags.e_islandFlag;
//island.Add(contact);
//// Has the other body already been added to the island?
//if (other.m_flags & Body.BodyFlags.e_islandFlag)
//{
// continue;
//}
//// Add the other body to the island.
//other.m_flags |= Body.BodyFlags.e_islandFlag;
//if (other.m_type != _staticBody)
//{
// other.SetAwake(true);
//}
//island.Add(other);
}
}
}
TimeStep subStep;
subStep.dt = (1.0f - minAlpha) * step.dt;
subStep.inv_dt = 1.0f / subStep.dt;
subStep.dtRatio = 1.0f;
subStep.positionIterations = 20;
subStep.velocityIterations = step.velocityIterations;
subStep.warmStarting = false;
island.SolveTOI(subStep, bA.m_islandIndex, bB.m_islandIndex);
// Reset island flags and synchronize broad-phase proxies.
for (int i = 0; i < island.m_bodies.Count(); ++i)
{
throw new NotImplementedException();
//Body* body = island.m_bodies[i];
//body.m_flags &= ~Body.BodyFlags.e_islandFlag;
//if (body.m_type != _dynamicBody)
//{
// continue;
//}
//body.SynchronizeFixtures();
//// Invalidate all contact TOIs on this displaced body.
//for (ContactEdge* ce = body.m_contactList; ce; ce = ce.next)
//{
// ce.contact.m_flags &= ~(ContactFlags.e_toiFlag | ContactFlags.e_islandFlag);
//}
}
// Commit fixture proxy movements to the broad-phase so that new contacts are created.
// Also, some contacts can be destroyed.
m_contactManager.FindNewContacts();
if (m_subStepping)
{
m_stepComplete = false;
break;
}
}
}
